Electric cable coupler



Feb. 16, 1960 Filed Feb. 1a. 1958 A. D. MARASCO ELECTRIC CABLE FIGJ COUPLER 2 sheets-sheet 1 INVENTOR.

AnfhonyD. Marosco BY wrham the grounding of wa er ourses Anthony D. Marasco, Norwalb-fionnl eassignortoll B,

N awe-Para:-

Nottingham -& Co Inc, rue rqrr New York,

Th s n n on e t i impr emen s in, ss r s Wi or cable coupling of connecting means.

n m ny ar a whe e s e t'e J e uipm nt s. u ed such as i du tr l pleats hemi al lab rat ries the umes o as s of easil i i ta le cha cter s ein?- q i ltl'y P esent h sk: r u r s the ex r i o e eme c r the use tion of sparks which might ignite 'such Turnes org Su s k. f rm t i connection with the use of' plugs and sockets for: electrically connectingmachines or equipment toa source oi current. 7 I V j: hf n he Headband-h d or man u ate slf fi tric al machines, or in the useof'machines, whereanoperator oi attendant may have bodily contact therewith, e A the rnachineas' asatety'nmeasu're is-im rt at d. hi s m a v' tr if s h ma h ne usedfin damp locations.

It is a particlar object ofifthe presen invention, in

view of the foregoing, top'rovide, a manner-as hereinafter more particularly set forth, a new coupling or of s c eq i nmq 9 ey i i'th f e:

Pa ti u a l lik l -w O r i 2,925,479 west rns. 1 use connectionwith the accompanying-drawingstorrning part of .the specification, ,with the"unders t and ing however; j that-the invention is not confined to a; strict'contormity v with the showing of the drawings may be changed or modified so long as such mark nomater ial departure from-the salient, features of the invention as-expressed-in the appended In the drawings:

Fig. ljis a view illustrating -in side elevation the plug and socket forming the new coupler of thepresent in vention, the socket part being illustrated-mounted upon the cover plate of a conventional -electric'al outlet box Fig. 2 isa view-showing the plug and socket or socketed receptacle joinedxtogether' with "the socketed receptacle. being shown in section and illustrating the plug in the first of two positions which it is caused to assume in the operation of establishing the connection and in which position the complete electrical connections between all current conducting elements have not been established; 1

Fig. 3 is a sec "'onalview' on anenlarged scale; taken versely of the receptacle socket and plug;

the soclcet' to its secondpositi I a n in which; ductors' are electricallyconnected;

Fig; 5 ..is.,a sectional view litaken'subs tantially on; the- 1 r I .plane of line 55 of 4 and showing the interior connector for joining electric current conductors which can be made and/or broken without producing open or' exposed sparks. V

Another object of the invention is to provide, in the manner as hereinafter set forth, a new coupling or connector of the character stated wherein grounding contacts are joined effected.

. fStillganother objector the invention is to'p'rovide a new p'lug and socket type coupler which is -so desigried that at least two manipulating acts' are required to 'be performed in joining the plug and socket to efiect closing A still iurther object of the'invention js to provide a new plug and socket type coupler wherein means-[is provided forlocking the'plug in. the socket against direct axial. withdrawal concurrently with the 'actofi efiecting electrical coupling of the enveloped pair s ot contacts.

coupler of the character described and by which to attain the hereinbefore stated objects, which is designed to effect the electrical joining together of grounding ter minals in advance of thecompletion of the :second act resulting in the electrical coupling of the-enveloped pairs,

one with the other before the actual closing of relatively movable current transferring-contacts is construction of the plug and the association of parts with contacts in the receptacle tor: socket;

Fig; 6 is a viewin' plan ofi one sidejoflthe' .sok'eted receptacle 1 showingone of the terrriinalsw-ith" which a I currentconductor is connected and showing the current" a carrying or hot' platewhich is embedded i of the receptacle, inldotted outline;

Fig. 7- is a view in perspectiveof hot plate showing-the circuit making. and: breaking unit a the insulation carried thereby "and'which unit embodies a sealed en'- velope and two" normally separated contacts therein;

. Fig.8 is a fragmentary detail-section on an. enlarged scale, taken'substantially on the ;line:8-'8 0t; Fig. 1.

Fig. 9 illustratesflanother form .of construction for the circuit making. and breaking unit wherein a spring element is 'housed within the envelope to assist in thesepa ration of the encased contacts; V V

Fig. 10 shows another embodiment of the :circuitiinak- 1 ing and breaking funit in which a spring is embedded in 0" thefiexible or resilient walllof'the envelope; 5 there-are shown the two principal vorprnajor parts of the 'Referring inow morerparticularly to -the drawings;

coupl'enembodying the plug part, 'which' is generally 1 designated 10, and the' socketed receptacle part which '60 Still another object of the invention is to provide a i e is lgenerally'd'esignate'd '12 and which is; formed 7 .to receive a portion of the plug part." I

The feceptacle' 1'2 =is-;.illust'rated as ;mountedlupon the cover plated-4 of a conventional type 'of' electrical out. let box'awhioh is shown in Fig; 1 in dotted outline and designated 16'. However; while =the'receptacle 12 will hereinafter be described.; with particular:relation ito the manner in which it is joined to the cover -plate14, it is to be understood that the coupling is not necess'arily limited .to the' mounting of the receptacle on a cover. plate of an outlet box, as :illustrated,but may bein the formof a molded terminal for a cable for'efiecting'the electrical connection zoracoupling. together 10f :two cable of contacts and while the ;-plug l-carried terminals are electrically joined to the cold contacts 'of- -saidpairs." V

Other objects and advantagesg of theinve' tion will" become apparentas the description of the same proceeds j and the invention will'be best understood from a con ends, .one of which carries the-plug? p"art*1'0- of ithei'ciranl acter shown.

*Theteceptaclepartcomprisesa z-molded rb'ddyxlliiiof a:suit'a;ble insulation'lmaterial which ay. be ,vulcaniz suitable material. j. -The body-isJ,hereishown;asllbeing su substantially on the line S -3 of Fig. 2 int; plane transthe underside of a'r ceptacle being designated 25, and, as shown, a portion of the receptacle material is extended through the opening 26 in the receptacle box cover plate and is radially extended on the front face of the cover plate to form the locking collar 27.

The body 18 has formed therein through the front face 25 and concentric with the collar 27,-the socket 23 which at its outer end is enlarged through a portion of its extent forming a first annular set-back 29 which joins a second annular set-back 30, of larger diameter and which constitutes the innersurface of the collar portion 27. e

The opposite sides of faces and 21 of the body '18 are formed in the molding of the body with shallow rectangular recesses 31 which are subsequently filled with the insulation material in the completion of the receptacle, as will hereinafter become apparent, and in this molding of the body there are also formed upon diametrically opposite sides of the socket 28the pockets 32 which areof insuflicient depth to merge with or intersect the wall of the socket 28. These pockets receive portions of the hereinafterdescribed terminal units each of which is generally designated .33 and one .of which is shown in perspective .in Fig. 7.

The wall of the cylindrical socket 28 is formed in the molding of the insulation body, with the diametrically opposite longitudinal guide grooves 34-which' lie in a planev at right angles to the' plane of the centers of the pockets 32. Each of these grooves is 'of a depth to have the bottom thereof fiush with the first offset 29 and at its inner end each of the longitudinal grooves 34 joins one end of an approximately quarter-circular groove 35 extending in the circumferential direction of the socket or concentric with the axis of the socket, and each of these quarter-circular grooves 35 intersects the inner portion of a pocket 32 as is clearly shown in Figs. 3 and 4. As shown in these last mentioned figures, the quarter-circular grooves extend from their respective longitudinal grooves 34 in the same circumferential direction so that one does not connect with the other.

At the bottom or inner end of the socket 28 the insulation body has a metal piece in the form of a block 36 embedded therein and exposed on the face 24 of the insulation body and a reduced bore 37 extends from the bottom or inner end of thesocket 28 to the block 36 and in line with this bore 37 the block 36 has a pit 38 therein for the purpose hereinafter set forth. This block 36 provides a grounding terminal with which asuitable ground Wire can be connected by means of the .screw '39 or in any othervsuitable manner.

The terminal units 33 which are fixed in and to the insulation body 18 at opposite sides thereof beneath the insulation covering faces 20 and 21, are of duplicate construction and, therefore, description of one applies to the 1 other and the same reference numerals will be applied has an aperture 42 in which is fixed the swaged over stud 43 carried by a.contact :.bu tton .44 which .is secured against the inner face of the plate 40. This contact or contact button 44 will be hereinafter referred to in the specification and claims as the hot contact, to facilitate distinguishing it from the about to be described coacting contact button which is cold or does not have direct connection with the hot plate and the hot wire of the electrical conductors.

Molded tothe inner face of the hot plate40, that is, the face against which the hot contact 44 is positioned, is an elastic-domeor envelope of insulation material'45 formed of an elastomer of suitable character, such as rubber, either natural or synthetic, plastic or the like. This dome or envelope 45, which is hermetically sealed to and against the inner face of the plate 40, carries a cold contact button 46 upon its inner side which is in opposed relation with the hot contact 44 and normally maintained spaced from the latter by the inherent tendency of the envelope dome to assume its normal shape.

The cold contact button 46 is electrically connected through a neck extension 47 passing through thewall of the envelope, with anend of a resilient contact strip 48. As shown, the contact strip 48 curves laterally and downwardly across the side of the envelope 45 to a laterally extending portion 49 of the insulation envelope, to which extension it is riveted or otherwise suitably secured, as indicated at 50. I V v The pockets 32 are suitably shaped .in the molding of the insulation body to receive the contacts enclosing envelope when the plate 40 is placed in position in the recess 31- and when the unit is so placed, the inner end of the contactstrip 48 which is attached to the cold contact button 46, will project into theadjacentt quartercircular groove 35. The units are placed in their respec-,.

tive recesses 31 so that the curving surface of the con-. tact strip 48 will be adjacent to that end of. the quartercircular groove which joins with'the longitudinal groove 34, the purpose of this arrangement being made clear hereinafter in connection with the description vof the. cooperating plug. v The insulation body 18 has molded therein adjacent to the corners of each of the recesses 31 a metal body or nut 51 for alignment with an aperture 41 of the adjacent plate 40 and the body 18 is alsoprovided, with a bore 52 leading from the plate aperture 41 to the threaded center of the nut body 51 to permit the passage of the threaded shank 53, of a securing and terminal screw 54. I

In the finished receptacle the insulation material will be disposed over the outer sideof the, hobp ates 40. and the securing and terminal screws 54and attachment of a current conducting wire to one of the terminal screws 54 is effected by removing or cutting away a necessary amount of insulation over the terminal screw to bare the latter so that it can be r emoved and the. conductor wire attached in the conventional manner. Fig. 8 illustrates such a conductor wire which'is desig-- nated 55 andwhich carries at its end a conventional eyed terminal 56 through which the screw 54 has its shank extended and when it is threaded up tightly in the nut 51- the eyed terminal 56 will be drawn into electrical. connection with the hot plate 40. V 7

Referring now to the plug part ofthe connector, it will be seen upon reference particularly to Fig. 5, that this comprises an elongate body 57 of a suitable insulation material such as that described in connection with the receptacle body 18, and this body 57 has a forward end portion which is stepped down in the two annular shoulders 58'and 59 to meet the elongate cylindrical terminal portion 60. a e

The terminal portion 60 of the plug part is:of a diam! eter to be received snugly in the circular socket 28 of.

' the receptacle and when the inner end face 61- of the portion 69, which is squaredwith theaxis of the plug, isagainst or in close proximity to the bottom of the, socket 2,8,; the annular, portions. 58Ha 1 5. Wi .be fitted,

' nga emen i h hs-hQ s i nt a iase t'- l .s

' Th resil n ntact st n- =sm1 t e rllexedl? dies-oi he esili nt. e ve pe stres in th ont s. wills rea is termed o an --s s sm forward e he em ari -cont the - body 57.

plug partso as'to proyideha continuous insulation prov tection-over all lQfIhG embeddediconductorst i The conductor astr ips '62wterminatefshort of the end face 61 f the terminalportion fifl in the. radially 1 outwardly extending 'contact heads 66; il'lhesetheads which are diametrically opposite one another iha-ye sloping outer or radially directed faces 67 and they iproject a suflicient distance beyond the side of the terminalextension-fil) .to. have vsliding engagement-in the longitudinalgroolves 734 whenthe extension portion :60, is inserted .into thetsocketu28. Also the heads 66 are spaced the tunerdistance from the portions i5=and59 s0 that whentthese are-firmly seated in the :set-backs and inthernannerstated, the headswill be in posi "on to enterthe quartercireular (grooveswhen the pl g QdY is otated n t e. proper direction. V

As Will be readily'seen upontreference-toliigst.3 and l, i when the plug is so uinsertecl'i-in the r ceptacle s c etand -is @given. clockwi e rotation, ths onta ths lsfifi wi 7 more thro e a jacent eu ere qul t oo e 4 and the-sl ping or nc ned 115 astest the -set wi r d ontmhe. curv g su faces o i si s t st st p 4 atl force" the o d' sont-a iioat asdly and into sl reve e ro ation th -nlue'to move he hea s hackinto he'innerendst elo tutli sl-- ov .4, st osepa a theontacts .4 i" -l he-es no v The cylind ic ten. i s a l. at t e salsa ib y has around, c ntest red mainta ned entrally xtendin on it din ll the ein 67a, which passes thro ghand bet een the co ducto s ps :62 b theead eaq fi and he: mi t ssas 69 l sss sr ss s e orm d; of re tizslvr ard' las s t rs i t t as 9 1? v-aste hth hot y s mewha re len and hi ashs si hsisss t ts l soils i sdi o the met sseaa stes? ti 1M" prote ts item t sett es-fillet this Plus oat l l P llr Qt nd for-mes a eater the "Pi ,i ayie'ths ss sndl n ts --@sr esdn he e 6 s l tsi a l connecte by a tubular solderless-butt connector ll with theiground wit 7 l i asses ou ard thmuh llsf alsc wi lug . cond o wir 54 and i -lsa'slss sl; i il p eathin fol tltiplsss ap wh h i ta i n as sa The "wh ufl na' n msatinthe man e stited in l nr s d ahems 'aa t ma then e sa y: us no only iin atmosphere'zcontaining" explosive gases bu areas which are or may be wet most of the time, such-as i in unhres ror'iaround ships, andid ckss Byhthe :provisionof the, annular-setbacks in the socket V and the ribs :orvcirlculart portions on the plugbody, these parts can hew-tel'escopedtogether in a fluid and gas tight coupling: which will prevent the entrance of moisture into the Esocket'when' the coupling is inuse,

In the installation'aofiwthc receptacle 12in an outlet-box it will be understood-that while cer i f mi a s,

are exposedlwithin the box; the admission of moisture thereto may be prevented where the box is completely embedded concrete 1017 the like. In such case, even though thesstnucture in. which the outlet box is housed may be submergsdrno water can enter the' socket when the :plug is connected therein. t 4- Whilettheinvention has -been illustrated :and described as embodying apair :of terminal units in the receptacle body 18 for cooperation with a pair of contact heads connected with wires 64;.-it;will 'be readily appreciated thatithezinve'ntion may-be incorporatedin a coupler corn;

prising: two :bodies 10, and 12 andtcarrying a single ter minal unit :and-sing levcqntactihead .66 for use in a series 7 connected electrical system. i

' 'Itwill be readilyaapparentofrom the foregoing descrim tioni'thatinwtheilse of the present coupler: when the 1 61' duced :end portion other the vplug :part. is inserted into the cylindrical-socket;28,.,=the :contact head 66? will enter and rideralongnn the longitudin g ove 4 unti h y: reach the1inner'iendssofaathe'grooves, at which time no he p u an aparts r ed b s me imdsiwe the qnt ets of h te ina units e;

o nl tsly nt nc i a sas d, iquid t h e c su es y: QQUI sith s' a the e-l s n of,

he-ean asts o -i the. parat n t er of wi be Wm:

inventions ar icu arl w ll. v 1n sdos s m dia-areas whet nfl ab e r exp osive ca es. a -r p to -be found d rnhadditi tosucliguse Ein-industrialplants,

chsm c lla o stofio and th i e the co plin s e c ass sslm is ss nea l way iprsss a The cou n y e u e b' s s t .3 oget nds. 'mu t -w s lab s w1l to m n au cially well adapted for use in mines where .bothnexplosive en o on mult s a ls ith sa i n o an 1 outl th ashstsh iii Fi 1-, 'Wh sm Pla eder c ne t ng; mul t't-wirs sabl lands tqse o th receptacle bodylfiqniay, s :hereinbe be cast with l wits s mnls l imilar o hs ia'wli sh't hestlis an -em sd lsi h ou i circuit zconnectionnwlill 'he.,nnade but, the ground contact at the; forwardfiend of the "plugwwill .hayefentered the pit or recess Q8iin athe ht dy :35 which wo ld hav be n previously connected to a ground wire. :After the axial extension f the .iglll'g :into the,Isoclnet in the manner stated, the outer eufd of the-socket wil ti htly c s d against the entrance ofmoisture by the firictional en segme hsno ti'ons .8 an li59 in they lse no t ons 30: and 22, resp ctively, a :h inhef re ta ednand he P g-may then-hemmed or otated a qua er tu so a to rid? ping end fa :67 o the c n act head 66 onto the metal conducto s 481 Si ce t ese con u ors project a substantial-distance nt he quarter-c rc ar o ves aim-hey wi l he exed outwardly, def rm n he ela ti e v pe. .45 in he llu rate n. ist 4 and forcing the cold IQQIIHQQES into s a y me l o meta con est-be ween .p m c -ti by e t na un s.- At-th a r snatk nerwhis om ths1=eu si eamqsp s re il ustra ed n F s-.3 5- an 7 o ved o enveloped ontacts aesi ieut is how; w ic has e n d sc be str' er strip 4 si s sil sm 'to tunstio hia additi n to its a ed funeiqmot prov d ng aw per 1 sew r.- whi h h act a p s w h t e. es l en snhsad u dsl a sp n re Be iassnatat asfihs qnt ttsl .--Q- l .sr resilient m a m b sa p o e s ind p nden ly-9r n a o iat n il erss l st i, n 48;:a i lus rat d la d 9; otherspniiiamea s be d si ned be r against the lanesut aes-Qt the EQ QlQBPi wal i urge t e r turn ofthe envelope to its normal condition f ter being Whe :1

tlis es n t suitable smok r v lest ca e e V msntaw -th hot con acts- I usiitwi -be s e that ktl efisoc reit "w e-co p etely s d. e o the e.

In additionto the foregoing, such coil spring or other type spring enclosed in' the envelope or capsule or molded therein, may-be used along 'with the disclosed striker strip 48; Y i a In Fig. 9, for exam'ple,.there isshown a diaphragm or envelope 45a corresponding to that shown in preceding figures and hermetically sealed around its perimeter to a supporting plate 40a which may be of metal, if the unit is to be installed in the manner illustrated in Figs. 3 and 4, or it may be of rigid insulation material of a suitable character so that the unit may be fully embedded in a carrying body of insulation and electrical connection made with the hot contact 44a by a conductor 40b, as

illustrated.

The cold contact in this unit is designated 46a and the enclosed spring means above referred to -is designated 100 and is in the form of a one or two turn helix which bears at one end against the top of the plate 40a while at its other end it encircles and is free from engagement with the contact 46a and bears against the top of the envelope.

In Fig. there is illustrated a spring means within the envelope 45b which spring means is designated 101 and as shown is fully embedded in the body of the insulation envelope so that it is com'pletelyencased or covered by the insulation material. In this unit the other parts are shown as being the same as in Fig. 9, such other parts here comprising'the base 400 against one side of which the periphery of the envelope is sealed, while the hot and cold contacts are here respectively designated 44b and 46b and the current conductor connected with the hot contact is designated 40d. a

In the preceding description theenvelope 45 enclosing the spaced contacts 44 and 46 has been described as placed in a preformed or premolded recess in .the insulation body 12. a

The modified embodiments of Figs. 9 and 10 may also be so installed. However, in the molding of the insulation bodies, these units could be embedded in the insulation material, in the body wall, coincidentally with v the molding of the body. Of course, it will be obvious,

or understood, that in such operation of molding the units a substantial portion of the top of the diaphragm or capsule will be made to project into the socket so that it can be contacted either against the striker strip or against the exposed outer end portion of the cold contact by the terminal head 66 o fthe plug whenthe latter is placed in operative position in the-socket. Y

Also in addition to the foregoing, the diaphragm or capsule enclosing the spaced contacts could-be incorporated in the structure of the portion of the plug body which extends into the socket in a suitable manner so that either the striker strip orthe exposed outer portion of the cold contact would project beyond the side of the reduced portion of the plug for engagement against a terminal exposed in the socket. With this arrangement, it will be seen that 'with the'units embedded in the extended portion of the plug so that the said parts of the capsule or envelope are exposed or extended beyond the side of the plug, when the reduced portion of the plug is inserted into the receptacle the striker strip, or exposed part of the cold contact, will ride over a cooperating contact in the receptacle and the capsule or diaphrag'm will be compressed against the resistance of the spring striker strip and the resistance ofthe resilient capsule wall or, in the case ofthe embodiment shown in'Figs. 9 and 10, the capsule will be compressed against the resistance of the spring housed therein or embedded in the capsule wall.

' In addition to the foregoing arrangement, a capsule or envelope 'rnight be placed in any other desired or suitable'lo'cation 'to'be made effective for the closing 7 of an electric circuit by the application of another body thereagain'st, which other' body may be another-electric 87. such as a'buttondesigned to be manually pressed or pressed by a suitable force-applying element.

An example of another use of the capsule. would be its placement in or upon the advancing'end of the plug body to be compressed, for the closingof the contacts a and completion of an electric circuit, when the plug is sults may be obtained by the use of various other forms of spring, either placed within the capsule or embedded in the wall thereof.

I claim:

I. An electric cable coupler comprising two bodies of insulation, an electric current conductor secured to each body, one body having a cylindrical socket therein, the other body having a cylindrical portion extending therefrom and adapted to be axially introduced into 'said" socket, said socket having a first groove in and extending longitudinally of the wall thereof and joining at its inner end with an arcuate circumferentially directed second groove, an electric terminal unit embedded in said one body and embodying a first contact having a portion projecting into said second groove, said current conductor in the one tody being electrically connected to a second contact in said unit adapted to be'electrically joined to a part of said first contact, a terminal head carried'by and projecting radially from said cylindrical portion of said other body and electrically connected to the current conductor in said other body, said terminal head being adapted to ride .in said grooves when said portion is axially introduced into the socket and then axially rotated and said terminal head engaging said first contact portion of the unit and effecting establish ment of electrical connection between the current conductors of said bodies upon completion of said axial rotation of said cylindrical portion.-

2. The invention according to claim 1, wherein the outer end portion ofthe socket and a part of said other body encirclingthe cylindrical portion are formed to have interfitting fluid tight engagement when the cylindrical portion is substantially fully extended into the socket, forming a fluid tight joint closing and sealing '5.'The invention according to claim 3, with means a formed at least in part of an elastomer, enveloping and forming a fluid and gas tight enclosure for the electrically joined parts of saidcontacts, and-said elastomer part carrying the cold contact and embodying a part ofthe first stated means.

6. The invention according to claim 1, wherein said terminal unit embodies, a metal plate embedded in the said one body and having the current conductor electrically connected thereto, the said second contact being.

a .hot contact joined to the plate, the said first contact being a cold contact, means supporting the cold contact in opposedrelation with and insulated from the hot contact,- said means yieldingly urging the cold-contact away fromthe hot contact, and a current conductor element joined to the cold'contact and being thesaidportion projecting into the second groove.

the pair of hot and cold contacts,

7 The raven-n65 asserting; sai d meanssiipporting-the-cold c'onitic mpnse an elastomer dome bonded to said rplate'and 91161051112 8, The iiivention'ac'cbiding tot M carrie'dby said one-body adapted to live a grounded conductor connected therewith, a grounding conductor passing through said cylindrical portion ofthe other body, and means for efiecting electrical coupling of the last terminal and the grounding conductor coincidentally,

with the substantial completion of the axial movement of the said cylindrical portion into the socket.

9. The invention according to claim 6, wherein the said means supporting the cold contact comprisesin part a dome-like cover over the hot contact and bonded to the metal plate and supporting the cold contact therein, said cover being formed of an elastomer, and said current conductor element comprising a flexible 'rnetal strip secured at one end to and insulated from the plate and having its other end engaging the outside top surface'of said cover and electrically connected therethrough to the cold contact.

l0. A coupler for electric current conductors comprising a first body of insulation having a socket therein, a second body of insulation having an elongate portion adapted for insertion in said socket and formed to' tightly lic strip secured at one end to said exposed metallic element and curving downwardly over the outer side of the fit inv and establish a gas and liquid tight seal with'the wall of the socket, a pair of electric terminals in said socket adapted to have current conductors. connected therewith, a pair of electric terminals carried by and exposed on the surface of. said elongate portion, means for restricting said portion of the plug to a fixed path upon axial insertion to a limited extent into the socket whereby the plug terminals are stopped in spaced relation to the socket terminals, means facilitating movement of the plug terminals into electric connection with the socket terminals followinginsertion of the plug to said limited extent, and means for electrically connecting current conductors to the plug terminals.

11. A coupler for electric current conductors comprising a receptacle body of insulation having a plug socket therein, a plug body of insulation constituting having a terminal extension adapted for insertion into said socket, a-pair of terminal units, embedded in the insulation material on opposite sides of the receptacle body and each comprising a fixed contact and a movably supported contact, means for connecting electrical conductors to the fixed contacts, said sockethaving a pair of longitudinal grooves in the wall thereof each' joining at its inner end with a substantially quarter-circular groove,

each quarter-circular groovepassing across an d exposing a current conducting portion of' a movably supported contact, current conductors extendinglongitudinally in said terminal'extension, of the plug, a terminal head foreach conductor projecting laterally from said extension and adapted to move in said longitudinal and quartercircular grooves upon axialinsertion and rotationalmoveenvelope toward the plate and secured at its other end toand electrically insulated from the plate.

17. A coupler for electric current conductors comprising a first body of insulation material having a socket therein, a second body of insulation material having an elongate plug portion adapted for insertion into said socket, an electric current'conductor having a terminal end embedded in the insulation materialof the firsttbody,

an electric current conductor having a terminal end embedded'in said plug portion of. the second body, at least two cooperating electric current conducting parts carried by the insulation bodies and exposed at least in part for cooperativeas'sociation respectively in the socket and upon the outside of the plug portion, said parts,

being electricallyconnected to the electric current conductors in their respective insulation bodies, said parts being electrically joined when the plug portion is in operative position in the socket, and one of said two parts embodying in its structure a pairof electrically isolated contacts and a resilient means operatively' connected therewith and urging electrical separation thereof, and'said contacts being urged into electrical connection against the resistance of said resilient means by the plug portion when the latter is in said operative position in the socket.

18. The invention according to claim 17, wherein the said one of said two parts further embodies in its structure a closed hermetically sealed envelope of resilient material constituting at least a part of the said resilient means.

19. The invention according to claim 17, wherein the said resilient means'comprises a resilient envelope enclosing the contacts and hermetically sealed against the entrancerof fluids thereinto,-and a spring means connected with the envelope.

' 20.- As an article of manufacture, an electrical terminal unit comprising'as an'integral structure a base body, a

hollow substantially semi-spherical elastomer envelope hermetically sealed around its perimeter to the base body,

ment of the portion in the socket, and said terminal 3 heads being arranged to'ride onto said exposed current conducting portions of the movable contacts and move the latter into engagement 'With the fixed contacts.

12. The invention according to claim 11, wherein'the said fixed and movable contacts are encased in a gas and liquid tight envelope. I V

13. The invention according to claim 11, wherein said socket at its outer end is defined by. an annular. offset and said plug hasan annular shoulder adapted to fittightly in saidofiset to form 'a gas and liquid tight joint. 7

14. The inventionaccording'to claim 11, in combination with an electric outlet box cover plate having an opening, said receptacle body being bonded to the inner side of said cover platewitli the socket directed through 1 and concentric with said opening, a portionof the re-' ceptacle body being extended through the plateopening acontact within the envelope and secured to said base body, means for connecting an electrical'conductor to said contact, a second contact fixed to the inner wall of the envelope'in radially spaced relation with thefirst contactandelectricallyisolated from the first contact by the: envelope, and a metallic fterminal element connected with the'second contact and extending through and exposed on theouter side of the wall of the envelope.

21. The invention according to claim-20, with a spring urgingelectrical'separation of said contacts.

22. T he invention according to claim 20, with a spring member enclosed within the envelope and exerting pres- ,sure against a wall of the envelope and against the basebody to.resiliently-resist the movement of said contacts together. 1

2-3. Theinvention according to claim 20; with a spring means embedded in the ,ela'stmer wall of the envelope and resisting movement'of 'sid contacts together.

Rferenee Cited in the file of this patent UNITED STATES PATENTS V 5 2,440,943 Gonsett et a1. May 4; 1948 12 Goodrichtetr al. July 21, 1953 Kellogget a1. Apr. 2, 1957 Dixbn Nov. 5, 1957 Marasco et' al. Feb. 18, 1958 'Sambonet July 22, 1958 

